Monel 400 Flat Washers manufactured at TorqBolt are corrosion resistant,high temperature resistant with ultimate tensile strength.
Dimensional standards as per DIN 125,ISO 7089,ISO 7090,ISO 7092,DIN 433,DIN 7349,DIN 9021,ISO 7093,F436,BS 4320,UNI 7064 are provided.
The raw material of these fasteners is renowned as registered trademarks like monel alloy 400. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. Monel 400 Flat Washers are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
Monel 400 Flat washers distribute clamp load over a wider bearing area, prevent surface damage, and accommodate bolt-hole oversize. TorqBolt manufactures Monel 400 Flat washers per ASME B18.21.1 / B18.22.1, DIN 125 / 126 / 127 / 9021, and ISO 7089 / 7090 / 7093 / 7094, in metric (M3–M100) and imperial (#4–4") sizes.
Plain Washer Dimensions
Monel 400 Flat plain washers are characterized by three critical dimensions: ID (clearance over bolt diameter), OD (load distribution area), and thickness (compressive stiffness). Standard tolerances are h13 on OD and H13 on ID per ISO 286-2; flatness 0.05 mm/100 mm and parallelism 0.05 mm/100 mm verified per lot. Edge break / chamfer per drawing.
Form Variants
Form A (regular) — DIN 125-A / ISO 7089, the default plain washer
Form B (large OD) — DIN 9021 / ISO 7093, for soft mating surfaces
Form C (heavy) — DIN 7349 / ISO 7094, for slotted holes / structural use
Spring (split) — DIN 127 / ASME B18.21.1, helical anti-vibration
Conical / Belleville (DIN 6796 / 2093) — preload maintenance
Hardness & Surface
Monel 400 Flat washers are hardness-controlled to balance load-distribution stiffness against surface damage to mating parts. Typical Vickers HV ranges: plain 140–180 HV; spring 380–440 HV; Belleville 460–540 HV. Surface finish Ra 1.6 µm or better; on critical sealing applications, Ra 0.8 µm available.
Special Patterns
TorqBolt produces Monel 400 Flat washers in square (DIN 436), fender (oversized OD), tab / lock-tang (DIN 462 / 463), and spherical seat washer + cup combinations. EN 10204 3.1 / 3.2 material certificates standard; NACE MR0175 / ISO 15156 on request.
Monel — Nickel-Copper Alloys
Monel alloys are 67% Ni / 33% Cu solid-solution alloys distinguished by uniform corrosion resistance in seawater, hydrofluoric acid, alkalis, and salt brines — environments where stainless steels fail by chloride pitting or copper-bearing alloys fail to alkalis. Monel was the first commercial nickel alloy and remains the default for offshore + chemical-processing fasteners requiring HF resistance.
Monel 400 (UNS N04400) is the base composition supplied in the as-annealed or hot-finished temper. Yield strength is moderate (~240 MPa min) but toughness extends to cryogenic service. Monel K-500 (N05500) adds Al + Ti for γ' precipitation hardening, raising yield to ~620 MPa after age hardening per AMS 4676 — the standard for high-strength shafting and fasteners in seawater. Monel R-405 is a free-machining variant.
Monel fasteners are produced per ASTM B164 (rod/bar) and supplied with EN 10204 3.1 / 3.2 certificates including stress-corrosion testing. Galvanic compatibility with copper-nickel piping makes Monel the natural mate for naval, desalination, and salt-evaporator service. NACE MR0175 sour-service compliance maintained when stress is below the SSC threshold for the specific heat-treat condition.
